The present invention generally relates to a mechanical device for releasably coupling truss structures and is specifically directed to an apparatus adapted to simultaneously join, with complete and uniform rigidity, the aligned ends of chord members of trusses, particularly trusses of the types commonly used to erect temporary entertainment stage environments.
Truss structures are staple equipment of entertainment industry productions. Music concerts, theatrical shows and other types of outdoors spectator events typically require stage platforms upon which the performances take place, elevated light fixtures and sound speakers to hover about the stage and inclined areas for the audiences to sit and view the performances. Normally, multiple truss sections are assembled to form structures for supporting the stage and retractable bleachers and for suspending speakers and lights. Obviously, the types of trusses used are selected for their ability to support loads that they are likely to experience. It is, therefore, imperative that any connectors used to join these trusses together be able to withstand any static and dynamic loads that they may be subjected to and that the connectors not be likely failure points along the assembled truss structures. Furthermore, where the stage environment may require quick reconfiguration, such as may be necessary during intermission of a multi-act concert, it is equally vital that the truss connectors lend themselves to rapid assembly and disassembly of trusses sections.
There are several varieties of truss connectors of the prior art adapted to facilitate relatively quick releasable coupling of the terminal ends of truss sections. Some such truss connectors feature forked configurations that allow chord members of adjacent truss sections to be joined at their aligned ends. For example, U.S. Pat. No. 6,675,546 to Coles discloses a connector comprising a male member and a forked female member, both having distal ends which are to be inserted into the ends of adjacent truss chord members and then secured to those chord members with cotter pins that are inserted into aligned holes residing in the connector members and truss chord members, and wherein the connector's male member is to be inserted into the forked female member and secured thereto with a clevis pin, thereby hingedly fastening the adjacent truss chord members together. However, while the connector disclosed in the Coles patent may be an effective truss coupling means, it, like many other truss connectors of the prior art, may have a particular vulnerability. Specifically, pins used to fasten components are subjected to shear when loads acting upon the connector-joined trusses pull the trusses away from each other.
U.S. Pat. No. 5,711,131 to Thomas discloses a truss also having connectors of forked configurations. More specifically, the Thomas connector features forked limbs with co-axial holes—allowing the limbs to be bolted to those of another connector—and a spigot to be inserted into a tubular truss member. Rather than using pins or bolts to secure the connector to the truss, the spigot is welded to the truss member that it is disposed within. However, because the forked connectors disclosed in Thomas are irremovable from the truss members that they are welded to, these trusses can be incompatible for coupling with other trusses that do not employ the same connector parts.
U.S. Pat. No. 6,634,823 to Sciortino discloses another style of truss connector comprising left and right shell pieces that are fitted over opposite sides of abutting truss member ends and then are screwed and bolted to those truss members. However, similar to the Coles connector, the configuration of the Sciortino apparatus renders its securing bolts and screws susceptible to failure due to shearing forces that may be induced by dynamic loads on the connected truss sections. Moreover, virtually all tube-to-tube truss connecting devices of the prior art of which the present inventor is aware, whatever their unique configurations, require their users to manually secure each joining of truss members one joint at a time. For example, when two truss sections are to be coupled at the ends of their four respective chord members, one normally must undertake piecemeal installation of four separate connector devices in order to secure each of the four chord member couplings. Obviously, when a great number of truss sections must be assembled, installing the necessary number of truss connectors can be a tedious, time consuming proposition. Furthermore, in circumstances where there is minimal time to perform such assembly work (ex: between concert acts), this realization could induce operations personnel, in their hast, to make mistakes relative to properly securing each truss member coupling and, consequently, cause the overall truss assembly to be structurally unsound.
Therefore, it can be appreciated that there exists a need for a truss connector apparatus that is adapted to: (a) facilitate more rigid and secure assembling of trusses and (b) allow the multiple aligned ends of chord members of separate truss sections to be coupled simultaneously for the purpose of reducing the work time associated with properly connecting trusses. The truss connector of the present invention substantially fulfills this existing need.